package nabble.naml.compiler;

import java.io.StringWriter;
import nabble.model.Init;


class BlockWrapper {
	private static final int blockWriterLimit = Init.get("blockWriterLimit",10 * 1024 * 1024);

	private final Chunk block;
	private final RunState runState;

	BlockWrapper(Chunk block,RunState runState) {
		this.block = block;
		this.runState = runState;
	}

	private static class BlockWriter extends TemplatePrintWriter {
		private final StringWriter sw;
		private boolean isNull = false;

		BlockWriter(StringWriter sw) {
			super(sw);
			this.sw = sw;
		}

		public void print(Object obj) {
			if( obj == null && sw.getBuffer().length() == 0 && !isNull ) {
				isNull = true;
				return;
			}
			super.print(obj);
			checkSize();
		}

		public void print(String s) {
			if( s == null && sw.getBuffer().length() == 0 && !isNull ) {
				isNull = true;
				return;
			}
			super.print(s);
			checkSize();
		}

		private void checkSize() {
			if( sw.getBuffer().length() > blockWriterLimit )
				throw new RuntimeException("BlockWriter too big");
		}

		String value() {
			if( isNull ) {
				if( sw.getBuffer().length() > 0 )
					throw new NullPointerException("null written to stream");
				return null;
			}
			return sw.toString();
		}
	}

	public final String toString() {
		BlockWriter out = new BlockWriter(new StringWriter());
		printTo(out);
		out.close();
		return out.value();
	}

	void printTo(IPrintWriter out) {
		block.run(out,runState);
	}
}